1. Field of the Invention
This invention relates to reversibly operable vehicles and in particular to means for signalling a back-up of the vehicle prior to the initiation of back-up motion.
2. Description of the Prior Art
One conventional method of signalling the back-up of a vehicle, such as a truck or the like, is to provide a signal-operating switch engageable by the gearshift levers of the truck when they are shifted to a reverse drive position. An illustrative form of such a back-up safety signal is shown in U.S. Pat. No. 2,829,213 of William J. Brett. Brett teaches the provision of the signal control in the transmission housing comprising switch operating means for operating a switch carried by the housing for operation when the control "is moved into the position in which the transmission is in reverse drive".
Seiji Kirimoto et al, in U.S. Pat. No. 3,439,324, show a backup warning device for a vehicle which is actuated by a gearshifting linkage when the control is placed in reverse. In the Kirimoto et al patent, a switch is closed by the shifting of the gearshift lever to the reverse position.
Another form of motion alarm for vehicles is illustrated in U.S. Pat. No. 3,827,024 of Arlynn W. Anderson et al, which patent is owned by the assignee hereof. In the Anderson et al patent, a motion alarm is provided which is actuated by elements of the vehicle drive system which not only operates the audible alarm when the vehicle is deliberately backed up, but also operates the alarm as a result of unexpected motion occurring in either direction as when the vehicle has been parked and is unattended. A logic circuit is provided to prevent operation of the alarm when forward motion of the vehicle is deliberately intended. When the shifting lever is shifted to the reverse position, a magnet is caused to close a reed switch to initiate sounding of the audible signal. In addition, the control activates the signal device by other operating conditions of the vehicle.